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United States Patent 9 PYRAZOLONES AND PROCESS FOR THEIR MANUFACTUREHans Bolliger, Basel, Switzerland, assignor to Ciba Limited, Basel,Switzerland, a Swiss firm Application January 25, 1954, Serial No.406,088

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The present invention is based on the observation that new and valuablepyrazolones are obtained when an arylhydrazine of which the aryl radicalcontains an acylated sulfonic acid amide group, is condensed with anagent effecting pyrazolone ring-closure.

As such an agent there come into consideration compounds which arecondensable with hydrazines to form 3-methyl-5-pyrazolones, such asdiketene and acetoacetic acid derivatives, for example acetoacetic acidamides or esters, more especially an acetoacetic acid ester of analiphatic alcohol of low molecular weight such as acetoacetic acidmethylor ethyl ester.

The arylhydrazines with an acylated sulfonic acid amide group, used asstarting material, may contain the hydrazine group (NHNH2) and theacylated sulfonic acid amide group bound to any aryl radical, butpreferably to an aryl radical of the benzene series. As an acylatedsulfonic acid amide group there come into consideration sulfonic acidamide groups in which a hydrogen atom of the SO2NH2 group is replaced byan acyl radical, advantageously by one containing as an acyl radical theradical of an organic sulfonic acid, preferably an alkane sulfonyl- (e.g. ethane sulfonyl) radical or a benzene sulfonyl radical. In additionto such an acylated sulfonic acid amide group and the hydrazine group,the aryl radical of the hydrazine compound concerned may contain furthersubstituents of a water-insolubilizing kind, such as alkyl or alkoxygroups, halogen atoms or nitro groups.

These arylhydrazines can be prepared from the appropriate arylamines bymethods in themselves known by diazo-.

tization and reduction, for example with alkali bisulfites or stannouschloride. As examples of arylhydrazines thus obtained there may bementioned: l-hydrazinobenzene-3-sulfonic acid-N-(benzoyl)-amide,l-hydrazinobenzene-3-sulfonic acid-N-(benzene sulfonyl)-amide,l-hydrazinobenzene-4-sulfonic acid N (benzene sulfonyl)- amide,l-hydrazinobenzenel-sulfonic acid-N-(para-toluene suIfOuyD-amide, 2chloro-l -hydrazinobenzene-5-sulfonic acid-N-(benzene sulfonyD-amidc,2:6-dichloro-lhydrazinobenzenel-sulfonic acidN-(benzene sulfonyl)-amide, 2:S-dichloro-1-hydrazinobenzene-4-sulfonic acid- N- (benzenesulfonyl)-amide, 4-chloro-l-hydrazinobenzene-S-sulfonic acid-N-(benzenesulfonyl)-amide, l-hydrazinobenzene 3 sulfonic acid-N-(par'a-chlorobenzene sulfonyl)-amide, l-hydrazinobenzene-3-sulfonicacid-N- (2 5-dichlorobenzene sulfonyl) -amide, l-hydrazinobenazene-3-sulfonic acid N-( 3 :4'-dichlorobenzene-sulfonyl)- amide,4-methyl 1 hydrazinobenzene-3-sulfonic acid-N- (2 5'-dichlorobenzene-sulfonyl) -amide, l-hydrazinobenzene-3- or -4-sulfonicacid-N-(ethane sulfonyD-amide.

The condensation of these hydrazine compounds with an acetoacetic acidderivative can, if desired, be carried out in an organic solvent oradvantageously in an aqueous medium. The reaction is carried outadvantageously in a nearly neutral to weakly acid medium, for example byadding acetic acid and alkali acetates, when using an acetoacetic acidamide, whilst in the case of acetoacetic acid esters the reaction ispreferably carried out in the presence of alkalis, for example sodiumcarbonate or sodium hydroxide.

In most cases condensation begins at a low temperature, for example atroom temperature. It is usually carried out however by heating thereaction mixture, for example to boiling point of the reaction mixture.

The pyrazolones obtained are now. They contain an aryl radical with anacylated sulfonic acid amide group, preferably one of the formula inwhich X represents a saturated aliphatic hydrocarbon radical or abenzene radical. These pyrazolones, more especially the1-aryl-3-methyl-5-pyrazolones of this kind, are valuable intermediateproducts, particularly for the manufacture of azo-dyestuifs.

It is in many respects surprising that the present process works sosmoothly, particularly because it could be expected that the acylatedsulfonic acid amide group would be hydrolysed under the mentionedreaction conditions.

The following examples illustrate the. invention, the parts andpercentages being by weight unless otherwise stated and the relationshipof parts by weight to parts by volume being the same as that of thekilogram to the liter:

Example 1 31.2 parts of 3-aminobenzene-l-sulfonicacid-N-(benzene-sulfonyl)-amide are dissolved in 125 parts of watr whileadding 5.3 parts of anhydrous sodium carbonate. After the addition of6.9 parts of sodium nitrite, the mixture is entered, while stirringthoroughly, into a mixture of 100 parts of ice and 10 parts by volume ofsulfuric acid (d=1.8). After 20 minutes the precipitated diazoniumcompound is filtered 01f rapidly and introduced into an ice-cold mixtureof 45 parts by volume of a sodium bisulfite solution (containing 550grams of NaHSOa per liter of solution), 22 parts by volume of a sodiumhydroxide solution of 30% strength and 30 parts by volume of Water. Thewhole is stirred for an hour at 0 to 5 C., 2 hours at 20 C., heated tothe'boil and parts by volume of hydrochloric acid (d=1.l8) are addeddropwise in the course of half an hour. After a further 20 minutes at C.the whole is cooled to 20 C. and filtered. The crystalline precipitateis dissolved in parts by volume of water with the addition of 5.3 partsof anhydrous sodium carbonate. After adding 13 parts by volume of acetoacetic acid ethyl ester dropwise, the whole is heated at the boil for anhour. 18 parts by volume of hydrochloric acid (d=1.18) are then addeddropwise to the hot solution and allowed-to cool while stirring. Afterfiltering and drying there is obtained the l-phenyl-3-methyl-5-pyrazolone-3-sulfonic acid-N-(benzene sulfonyl)-amide of theformula which can be recrystallized from much water for purification.The new product is a faintly yellowish colored powder which forms ayellow water-soluble dyestufi in a Weakly alkaline aqueous solution withphenyl-diazonium chloride.

Example 2 264 parts of 4-aminobenzene-l-sulfonic acid-N-(ethanesulfonyD-amide are heated in 250 parts of water with 230 parts by volumeof hydrochloric acid (d=1.18) to 60 C., 700 parts of ice are added and,while stirring vigorously, a solution of 69 parts of sodium nitrite in200 parts of Water is added dropwise in the course of 10 minutes. Thewhole is then stirred for a further hour at +5 C. and the suspension isslowly added dropwise, while stirring, to a mixture of 450 parts byvolume of sodium bisulfite solution (550 grams of NaHSOa per liter ofsolu tion), 200 parts by volume of a sodium hydroxide solution of 30 percent. strength and 450 parts of ice. Thereupon the whole is stirred fora further 2 hours at 15 C.; the pH should be adjusted to 7-9, ifnecessary by adding hydrochloric acid. The almost colorless solution isthen concentrated to about half at 70-80" C. under reduced pressure, 260parts by volume of hydrochloric acid (d=1.l8) are added and the whole isheated for an hour at 90 C. After cooling to 50 C., the pH is adjustedto 7-8 by first adding 220 parts by volume of sodium hydroxide solutionof 30 per cent strength and then with which can be recrystallized frommuch water for purification. The new product is a faintly yellowishcolored powder which forms a yellow water-soluble dyestufi in a weaklyalkaline aqueous solution with phenyl diazonium chloride.

In the following table further pyrazolone derivatives are listed whichwere prepared according to the methods described in Example 1 or Example2.

Star ting Material Pyrazolone Method 1 CH; Example 2.

SO2NHSO:-C 2H5 I C=N\ CH=C I I SO2NHSOr-GzHs 0H 2"". CH; Example 1.

NH2- 5 O zNHs O I GH=C 3 C H: DO.

C1 S OZNHSO G1 e43 CH=C S O ZNHS O H 4 01 CH: Do.

I J; Cl

:N I NH S OZNHS O a /N S 0 zNHS O 3-- l CH=C 5 Cl C H: DO.

=N NHzso zNHS 0,

/N SOZNHS 0 Cl CH -C I) C 1 H 6 ('31 CH: Do.

so NHSO I 1 I NHz CH=C I I S OZNHSO 0H 7 OH: DO.

S OHNHS 0 C1 6 I :N\ NE; J: /N

l OzNHSO 01 on Starting Material Pyrazolone Method 8 Cl CH: D0.

:N Osomnso,

I l 2 43 a NH: 1 CH=C A I OaNESOz- OH 9 Cl CHI D0.

=N SO:NHSO C1 l 01 NH: H=C

I SOQNHSO 0H 10.....- CH: Cl CH1 D0.

=N BOaNHSO i /N CHI Cl 1 Hzc OINHSO (BE; wherein R represents a memberselected from the group consisting of the benzene and chlorobenzeneradicals and R1 represents a member selected from the group consistingof the benzene and chlorobenzene radicals and the saturated loweraliphatic hydrocarbon radicals.

2. A -pyrazolone of the formula wherein two of the Xs represent chlorineatoms and the other two hydrogen atoms.

3. The S-pyrazolone of the formula in. 4. The S-pyrazolone of theformula CH: 5. The 5-pyrazolone of the formula I 01 o-mOsomnsmQ 6. The5-pyrazolone of the formula /(J Q-somnsm-O HC/ I 7. The S-pyrazblone ofthe formula H0 a- Q HC I S 0 :NHS 0 8. A process for the manufacture ofa 5pyrazolone wherein an arylhydrazine of the formula wherein Rrepresents a member selected from the group consisting of the benzeneand chlorobenzene radicals and R1 represents a member selected from thegroup consisting of the benzene and chlorobenzene radicals and thesaturated lower aliphatic hydrocarbon radicals is heated with anacetoacetic acid ester of an aliphatic saturated alcohol containing upto two carbon atoms in an alkaline aqueous medium.

9. A process for the manufacture of a S-pyrazolone wherein anarylhydrazine of the formula wherein R represents a member selected fromthe group consisting of the benzene and chlorobenzene radicals and R1represents a member selected from the group consisting of the benzeneand chlorobenzene radicals and the saturated lower aliphatic hydrocarbonradicals, and an acetoacetic acid ester of an aliphatic saturatedalcohol containing up to two carbon atoms are heated together in analkaline aqueous medium at the boiling temperature of the reactionmixture.

References Cited in the file of this patent UNITED STATES PATENTS Schmidet al. Aug. 8, 1950

1. A 5-PYRAZOLONE OF THE FORMULA